The present disclosure relates to a solid-state imaging element, a manufacturing method, and an electronic device, in particular, to a solid-state imaging element, a manufacturing method, and an electronic device where it is possible to obtain images with a more favorable image quality.
In the related art, for example, solid-state imaging elements such as Charge Coupled Device (CDD) or Complementary Metal Oxide Semiconductor (CMOS) image sensors are used in electronic devices which are provided with an imaging function such as a digital still camera or a digital video camera. The solid-state imaging elements have pixels where a photodiode (PD) which performs photoelectric conversion and a plurality of transistors are combined and images are constructed based on pixel signals which are output from a plurality of pixels which are arranged in a plane.
Such solid-state imaging elements are configured such that the pixels are physically separated from each other. For example, the separation between the pixels may be performed using a structure where trenches are cut out between the pixels and an insulation film, organic material, metal material, or the like is filled in the trenches.
For example, the present applicant proposed an imaging element where a pixel separation region is formed with a structure where trenches are cut out between the pixels by dry etching, a fixed charge film and an insulation film are formed in the trenches, and a light shielding film is filled in thereon (refer to Japanese Unexamined Patent Application Publication No. 2013-128036).
In the imaging element, for example, hafnium (HfO2) or the like is used as the fixed charge film and either of a metal material (Ti, W, Ta, Al) or a black material (carbon black, TiO, FeO) is used as the light shielding film. Due to this, in the imaging element, it is possible to suppress generation of color mixing by reflecting or absorbing obliquely incident light, which is a mixed color component, in the pixel separation region.
Furthermore, the present applicant proposed an imaging element where a pixel separation region is formed with a structure where an inorganic material which absorbs light or a photosensitive resin which includes a black pigment is filled in trenches and a metal light shielding film (W, Ti) is formed on top of the trenches (refer to Japanese Unexamined Patent Application Publication No. 2012-175050).
In the imaging element, for example, by adopting a configuration which uses an inorganic material, it is possible to absorb light with a short wavelength in the blue color region which is not able to be shielded by a light shielding film of an upper layer using a wide band gap of the inorganic material, and it is possible to reduce color mixing. In addition, by adopting a configuration which uses a photosensitive resin, it is possible to selectively absorb incident light up to a long wavelength in addition to the short wavelength by changing the composition of an organic film, and it is possible to reduce color mixing.